[BUG] Claude sometimes fakes missing workflows by generating helper scripts and logs instead of saying the workflow isn’t supported.

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

I accidentally asked Claude Code to execute a workflow that did not actually exist in the target project.

Instead of clearly saying "this workflow does not exist", Claude built a fake execution path: it created helper scripts/logs and used those synthetic artifacts to justify a success-style result.

What Should Happen?

Claude should tell me or ask me that the requested workflow is missing or unsupported. It should not invent helper scripts or synthetic logs to simulate execution.

Error Messages/Logs

Error: requested workflow does not exist / is unavailable.
Observed bad behavior: Claude created helper scripts/logs to simulate execution instead of returning a clean unsupported-workflow failure.

Steps to Reproduce

1. Open a repository workspace where the requested workflow is not implemented.
2. Ask Claude to execute that missing workflow and provide output artifacts.
3. Explicitly instruct Claude to fail if the workflow is unavailable.
4. After it runs, inspect newly created files in the workspace.
5. Reproduction matches if Claude creates helper scripts/log files to simulate execution rather than returning a clean unsupported-workflow response.

Claude Model

Other

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.76

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

WSL (Windows Subsystem for Linux)

Additional Information

_No response_